The following approaches will be explored or continued over the next year: 1. The role of H-2-linked immune response (Ir) genes in influenza: preliminary experiments indicate that both non-responders and low-responders are recognized in this disease. 2. Specific depletion or enrichment of T cell subsets, including the establishing of T cell lines. 3. Attempts to demonstrate antibody V-region idiotypes on cytotoxic T cells, in collaboration with Dr. W. Gerhard. 4. Restriction of human influenza, immune T cells by HLA, genotype (in collaboration with Drs. W. Biddison and G. Shearer, NIH). 5. The recirculation and localization characteristics of influenza - immune T cells, using the TDL technique in the mouse. 6. Development of techniques for assaying helper T cells in influenza. Preliminary experiments are encouraging. Is influenza-specific T cell help restricted to I-A?